I have downloaded the Fedora 16 64-bit ISO file about ten times (7 on XP Pro and 3 on F13). I have tried using direct downloads from the Fedora site, direct downloads from a mirror (tried that twice) and BitTorrent clients on each platform (Transmission on F13). Still no luck. All 10 files are corrupt.

Why is this happening? Interference in my house or neighborhood?

I thought BitTorrents checked the file for me? Why does it not report errors?

I did a manual verify using Transmission.

If it's hopeless I need to get a DVD from who knows where (any suggestions for reliable Web companies that sell them?).

For awhile, it was quite confusing--even the nice folks at distro watch were thrown off by the way the sums were listed.

However, looking at it now, it seems as if it should be clear that you want to use sha256, and shouldn't even be necessary to go to another page to figure that out. I'm curious why you used md5 sums (unless you're looking at an old mirror, where they still have it in the confusing way, but that doesn't seem likely.)

I used md5sum because I had several files and I wanted to see if any of them were the same as any of the others. If the files were not corrupted I would get the same sum with each file when I use md5sum.

Using the correct program to compute the sums does not alter the fact that the files are corrupt. When I use sha256sum it tells me the files are corrupt. I knew that would happen because all the files are different!

I always download using wget, which is a robust command-line tool, and have never had a corrupted download. You can try resuming a download with the -c option, in case your download is short (which is probably the most common form of corruption). If that's not the case, then as the other poster said, rsync will fix an arbitrarily corrupted download.

Torrent virtually can't download a bad data block - it's check-summed. So your error is caused either on the server or on your system. Since it's happened repeatedly on your system, it's the suspect. The disk will announce any uncorrectable errors - so that's very unlikely.

97% probability that you have a flakey DRAM stick.
Install memtest86+ then boot it and leave it to run overnight.

Sadly w/ today's technology most home systems don't have ECC or parity on DRAM - ridiculous.

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I used wget and copied the file from a mirror but it was still corrupted. (sha256sum did not match).

Then I used rsync and had the same problem: checksum still does not match. I will try rsync several times. I'm not sure what options to use with rsync. I am just using the --progress option which shows the progress.

I took out one memory stick and reran rsync on one of the corrupted downloads. Then when I ran sha256sum it said the file was OK.

Just for good measure, and to test my memory on a large data transfer (since rsync only took a few minutes), i.e. to double-check that the memory stick I removed was indeed the bad one, I reran wget and got another copy of the ISO file. I used sha256sum on this second ISO and it was also OK.